1. Field of the Invention
The present invention relates to image processing technology, and in particular relates to an apparatus or a method for eliminating flicker in a multi-exposure imaging system
2. Description of the Related Art
Cameras often use CMOS image sensors with an electronic rolling shutter. The electronic rolling shutter makes each line of the pixel array of the image sensor start an exposure procedure at a different time but with the same exposure duration. When the exposure duration is less than a half cycle of AC supply (for example, 1/60 second) or is not the exact multiple of a half cycle, each line of the pixel array of the image sensor captures a different luminance from flickering AC lighting fixtures such as fluorescent lamps, thus, producing alternating light and dark interlaced strips on an image. This is the so-called rolling shutter flicker.
A multi-exposure imaging system combines at least a short exposure image and a long exposure image of the same scene, for example, to increase the dynamic range of an image. Due to the shorter exposure duration of the short exposure image, the flicker problem caused by the unstable ambient light sometimes gets worse in multi-exposure imaging systems, and one usual flicker problem is caused by the rolling shutter flicker.
Therefore, it is desirable to provide a new apparatus or method for eliminating the rolling shutter flicker in the multi-exposure imaging system.